As a determiner, either has a similar meaning to the pronoun. It is about one or the other oftwo people or things, and it comes before a noun.
- I don’t mind which one. Just give me either one, please.
- There is a door at either end of the long corridor.
We may use either before a pronoun or to show something is happening.
- Either she is telling the truth or she does not know she is telling a lie.
- Either he or his brother is going to marry her.
As a determiner, neither is used to show not either of two people or things.
- Neither one of us is a smoker.
- “I have found these two coins.” “Neither coin is mine.”
A noun that follows either or neither is singular.
- You can choose either twin bed, and I will take the other one.
- He was punched hard on the nose, but neither nostril was bleeding.